Stator-less electric motor for a magnetic resonance imaging system and methods thereof

Abstract

A stator-less electric motor for an MRI system is provided. The stator-less electric motor includes a body, a rotor rotatable connected to the body, and at least one coil winding disposed on the rotor. The at least one coil winding is arranged so as to rotate the rotor when energized via an electrical current in the presence of a magnetic field generated by a magnet assembly of the MRI system.

What is claimed is: 
     
       1. A stator-less electric motor for an MRI system comprising:
 a body; 
 a rotor rotatably connected to the body; 
 at least one coil winding disposed on the rotor; and 
 wherein
 the at least one coil winding is arranged so as to rotate the rotor when energized via an electrical current in the presence of a magnetic field generated by a magnet assembly of the MRI system; and 
 the magnetic field is a leakage field outside of a bore of the magnet assembly. 
 
 
     
     
       2. The stator-less electric motor of  claim 1 , wherein the electrical current is an alternating current. 
     
     
       3. The stator-less electric motor of  claim 2  further comprising:
 a sensor disposed on the rotor and operative to measure a rotational speed of the rotor; 
 a rectifier operative to provide the electrical current; 
 an inverter disposed between the rectifier and the at least one coil winding and operative to govern the switching of the electrical current to the at least one coil winding based at least in part on the rotational speed of the rotor. 
 
     
     
       4. The stator-less electric motor of  claim 1 , wherein the electrical current is a direct current. 
     
     
       5. The stator-less electric motor of  claim 4  further comprising:
 a rectifier operative to provide the electrical current; and 
 a rotating inverter disposed between the rectifier and the at least one coil winding and operative to govern the switching of the electrical current to the at least one coil winding. 
 
     
     
       6. The stator-less electric motor of  claim 4  further comprising:
 at least one commutator brush operative to govern the switching of the electrical current to the at least one coil winding. 
 
     
     
       7. The stator-less electric motor of  claim 1 , wherein the rotor is operative to drive at least one of a blower and a liquid pump. 
     
     
       8. The stator-less electric motor of  claim 7 , wherein the blower is operative to cool at least one of:
 a patient disposed within the bore of the magnet assembly; and 
 one or more electrical components of the MRI system. 
 
     
     
       9. The stator-less electric motor of  claim 1 , wherein the magnetic field does not induce a magnetic force in the stator-less motor when the at least one coil winding is not energized. 
     
     
       10. A method of powering a stator-less electric motor comprising:
 generating a magnetic field via a magnet assembly of an MRI system; 
 energizing at least one coil winding via an electrical current, the at least one coil winding disposed within the magnetic field on a rotor rotatably connected to a body of the stator-less electric motor; 
 rotating the rotor via the at least one energized coil winding in the presence of the magnetic field; and 
 wherein the magnetic field is a leakage field outside of a bore of the magnet assembly. 
 
     
     
       11. The method of  claim 10 , wherein the electrical current is an alternating current, and the method further comprises:
 measuring a rotational speed of the rotor via a sensor disposed on the rotor; 
 providing the electrical current to an inverter via a rectifier, the inverter disposed between the rectifier and the at least one coil winding; and 
 switching the electrical current to the at least one coil winding via the inverter based at least in part on the rotational speed of the rotor. 
 
     
     
       12. The method of  claim 10 , wherein the electrical current is a direct current and the method further comprises:
 providing the electrical current to a rotating inverter via a rectifier, the rotating inverter disposed between the rectifier and the at least one coil winding; and 
 switching the electrical current to the at least one coil winding via the rotating inverter. 
 
     
     
       13. The method of  claim 10 , wherein the electrical current is a direct current and the method further comprises:
 switching the electrical current to the at least one coil winding via at least one commutator brush. 
 
     
     
       14. The method of  claim 10  further comprising:
 driving at least one of a blower and a liquid pump via the rotor. 
 
     
     
       15. The method of  claim 14  wherein the blower cools at least one of:
 a patient within the bore of the magnet assembly; and 
 one or more electrical components of the MRI system. 
 
     
     
       16. The method of  claim 10 , wherein the magnetic field does not induce a magnetic force in the stator-less motor when the at least one coil winding is not energized. 
     
     
       17. An MRI system comprising:
 a magnet assembly operative to generate a magnetic field; 
 a stator-less electric motor that includes: 
 a body; 
 a rotor rotatably connected to the body; and 
 at least one coil winding disposed on the rotor; and 
 wherein
 the at least one coil winding is arranged so as to rotate the rotor when energized via an electrical current in the presence of the magnetic field, and 
 the magnetic field is a leakage field outside of a bore of the magnet assembly. 
 
 
     
     
       18. The MRI system of  claim 17 , wherein the magnetic field does not induce a magnetic force in the stator-less motor when the at least one coil winding is not energized. 
     
     
       19. A stator-less electric motor for an MRI system comprising:
 a body; 
 a rotor rotatably connected to the body and operative to drive at least one of a blower and a liquid pump; 
 at least one coil winding disposed on the rotor; and 
 wherein the at least one coil winding is arranged so as to rotate the rotor when energized via an electrical current in the presence of a magnetic field generated by a magnet assembly of the MRI system. 
 
     
     
       20. A stator-less electric motor for an MRI system comprising:
 a body; 
 a rotor rotatably connected to the body; 
 at least one coil winding disposed on the rotor; 
 a sensor disposed on the rotor and operative to measure a rotational speed of the rotor; 
 a rectifier operative to provide an alternating electrical current; 
 an inverter disposed between the rectifier and the at least one coil winding; and 
 wherein
 the at least one coil winding is arranged so as to rotate the rotor when energized via the alternating electrical current in the presence of a magnetic field generated by a magnet assembly of the MRI system, and 
 the inverter is operative to govern the switching of the electrical current to the at least one coil winding based at least in part on the rotational speed of the rotor. 
 
 
     
     
       21. A method of powering a stator-less electric motor comprising:
 generating a magnetic field via a magnet assembly of an MRI system; 
 energizing at least one coil winding via an electrical current, the at least one coil winding disposed within the magnetic field on a rotor rotatably connected to a body of the stator-less electric motor; 
 rotating the rotor via the at least one energized coil windings in the presence of the magnetic field; and 
 driving at least one of a blower and a liquid pump via the rotor. 
 
     
     
       22. A method of powering a stator-less electric motor comprising:
 generating a magnetic field via a magnet assembly of an MRI system; 
 providing a direct electrical current to a rotating inverter via a rectifier, the rotating inverter disposed between the rectifier and at least one coil winding disposed within the magnetic field on a rotor rotatably connected to a body of the stator-less electric motor; 
 energizing the at least one coil winding via the direct electrical current; 
 rotating the rotor via the at least one energized coil winding in the presence of the magnetic field; and 
 switching the electrical current to the at least one coil winding via the rotating inverter.